SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db1b5582f25962aa6203ea1125c6176db508136d18675852b055517b881b6195' 
  AND token = 'TlG+GAtvUal1DG0WXsx57NCT9wdq1MYGW6kwbFzBzfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}